JP5872093B1 - Radioactive substance removal method and radioactive substance removal system - Google Patents

Abstract

A radioactive substance removal method and a radioactive substance removal system capable of effectively and stably performing effective removal of radioactive substances from an object to be treated by effectively suppressing energy consumption and generation of defective treatments. I will provide a. A radioactive substance removal system for executing a radioactive substance removal method includes a heat treatment unit (10) for performing a heat treatment for heating a treatment object, and a treatment object in the middle of the heat treatment in the heat treatment part (10). A radioactivity measurement processing unit 20 that measures the radioactivity, and a processing condition adjustment processing unit 30 that adjusts the conditions of the heat treatment in the heat treatment unit 20 based on the measurement results in the radioactivity measurement processing unit 20; The process condition adjustment processing unit 30 is configured to execute the process condition adjustment process before the heating process for the processing object whose radioactivity is measured in the radioactivity measurement process is completed. [Selection] Figure 1

Description

  The present invention relates to a technique for removing a radioactive substance from a processing object containing the radioactive substance.

  According to “Fukushima Prefecture's Policy on Disposal of Disposal Waste” (June 23, 2011, Ministry of the Environment) of incineration ash (an example of processing target) generated by incineration of disaster waste containing radioactive materials About handling, when radioactive cesium concentration (total value of cesium 134 and cesium 137) which is an example of radioactive concentration exceeds standard value of 8,000Bq / kg, storage in intermediate storage facilities is necessary If the value is below the above-mentioned standard value, the policy is that it can be landfilled at a general waste final disposal site (managed final disposal site). However, in order to promote landfill disposal, it is required to further remove radioactive substances from such incineration ash to further reduce the radioactive concentration of the incineration ash.

  In addition, since most of the radioactive materials in the waste migrate to the exhaust gas and adhere to the fly ash during the incineration process of the waste, the radioactivity concentration of the main ash is smaller than that of the fly ash and is below the above reference value. Often becomes. However, there is a possibility that the amount of main ash exceeding the above-mentioned standard value will increase in the future as volume reduction by incineration of decontamination waste in high-dose areas such as special decontamination areas is promoted. Therefore, in order to reduce the amount of main ash brought into intermediate storage facilities with limited storage capacity, it is possible to further remove radioactive substances from such main ash and reduce the radioactivity concentration of main ash. Desired.

  Therefore, as shown in Patent Documents 1 to 3, the incineration ash generated along with the incineration of disaster waste containing radioactive substances is heated after adding a volatilization accelerator such as a chloride compound (an example of heat treatment) Many techniques have been proposed to volatilize and remove radioactive materials from incinerated ash.

JP 2014-174090 A JP 2013-120146 A JP2013-122440A

However, in any of the above-described techniques, it is impossible to grasp the volatilization and removal status of the radioactive material from the incinerated ash during the heat treatment. Therefore, even if the radioactive material is not sufficiently volatilized and removed in the heating region, it may not be recognized, and there may be a processing defect in which the radioactive material is not sufficiently removed.
In order to suppress the occurrence of such processing defects, the conventional technology controls the heating process (condition adjustment) using the temperature in the heating region as an index. However, temperature is not a direct indicator of the volatilization and removal status of radioactive materials from incineration ash. Therefore, in order to remove volatilization of radioactive materials from incineration ash that is stable only by temperature control, removal of radioactive materials is not possible. It is necessary to heat in an excessive manner in consideration of a margin so as not to generate a sufficient processing defect, leading to an increase in energy consumption.
Separately from this, it is also conceivable to control the heat treatment by grasping the volatilization removal result of the radioactive substance from the radioactivity such as the radioactivity concentration of the incinerated ash after the heat treatment. However, in this case, the control of the heat treatment tends to be slow, and when a large number of objects to be processed are continuously heat-treated, the deterioration is already predicted at the time when the volatilization result of the radioactive material is grasped. Since there are many subsequent processing objects to be processed, it is not possible to obtain a sufficient effect of suppressing the generation of processing defects.

  In view of this situation, the main problem of the present invention is to grasp the state of volatilization and removal of radioactive substances during heat treatment, and to optimize the heat treatment conditions, thereby effectively reducing energy consumption and generation of processing defects. The object of the present invention is to provide a radioactive substance removal method and a radioactive substance removal system that can suppress and appropriately remove radioactive substances from a processing object efficiently and stably.

1st characteristic structure of this invention is a radioactive substance removal method which performs the heat processing which heats the process target object containing a radioactive substance,
Based on the measurement result of the radioactivity amount of the treatment object in the middle of the heat treatment, and the measurement result of the radioactivity amount of the treatment object in the middle of the heat treatment in the radioactivity measurement processing A processing condition adjustment process for adjusting the conditions, and the processing condition adjustment process is performed before the heating process for the object to be processed in the middle of the heating process in which the radioactivity is measured in the radioactivity measurement process is completed. Then, the remaining heat treatment is performed under the conditions after the adjustment by the treatment condition adjustment processing on the processing object in the middle of the heat treatment in which the radioactivity amount is measured by the radiation amount measurement processing,
The heat treatment is a treatment for heating the object to be treated while being conveyed inside a conveying heating furnace,
The processing target object in the middle of the heat treatment is that it is a processing target object located in the middle of the transport direction inside the transport-type heating furnace .

  According to this configuration, in performing the heat treatment for heating the processing object including the radioactive substance, by measuring the radioactivity amount of the processing object in the middle of the heat treatment by the radioactivity measurement process, It is possible to directly grasp the volatilization removal status of radioactive materials.

Then, based on the measurement result in the radioactivity measurement process, the processing condition adjustment process adjusts the heat treatment condition to an appropriate one according to the volatilization removal status of the radioactive substance, so that the object to be treated in the heat treatment The radioactive material can be appropriately volatilized and removed from the water. Moreover, since the processing condition adjustment process is executed before the heating process for the processing object whose radioactivity is measured by the radioactivity measurement process is completed, the remaining processing target for the processing object whose radioactivity is measured by the radioactivity measurement process is processed. It is possible to optimize the heat treatment and suppress the processing target from being deteriorated by the remaining heat treatment that has been optimized. Moreover, since it heats, conveying a process target object in heat processing, the efficient heat processing form which heats many process target objects sequentially and continuously can be taken.

Therefore, it is possible to effectively suppress energy consumption and generation of defective processing, and to efficiently and stably perform appropriate removal of radioactive substances from the processing target.
In the second feature configuration of the present invention, as the processing condition adjustment processing, the transport speed of the processing object inside the transport-type heating furnace or the temperature of the processing object inside the transport-type heating furnace is adjusted. There is in point to do.

The pre-Symbol radioactivity measurement processing may be performed at multiple time points different of the progress the heat treatment.

  According to the above configuration, since the measurement information of the radioactivity amount at a plurality of time points with different degrees of progress of the heat treatment is obtained in the radioactivity measurement process, the volatilization of the radioactive material as the volatilization removal status of the radioactive material is obtained from the measurement information at the plurality of time points. It is possible to grasp the progress (difference and tendency) of the removal, and it is possible to grasp the volatilization removal state of the radioactive substance during the heat treatment more accurately. Therefore, the heat treatment conditions can be adjusted to a more appropriate condition in the treatment condition adjustment process, and the generation of energy consumption and processing defects can be further suppressed.

The pre-Symbol radioactivity measurement processing may be performed at a plurality of locations in the conveying direction of the heat treatment.

According to the above arrangement, since the measured amount of radioactivity at a plurality of positions in the conveying direction of the heat treatment in Ino amount measurement processing release (multiple locations), it is assumed that the measurement points of radioactivity indicates the progress of uniquely heat treatment, It is possible to easily and reliably measure the amount of radioactivity at a plurality of time points with different degrees of heat treatment.

A third characteristic configuration of the present invention is a radioactive substance removal system that performs a heat treatment for heating a processing object containing a radioactive substance,
A heat treatment unit that performs the heat treatment, a radioactivity measurement processing unit that performs a radioactivity measurement process that measures a radioactivity amount of a processing object in the middle of the heat treatment, and the heat treatment in the radioactivity measurement process A processing condition adjustment processing unit that executes a processing condition adjustment process that adjusts the condition of the heat treatment based on the measurement result of the amount of radioactivity of the processing object in the middle of the processing condition adjustment unit, the processing condition adjustment processing unit The processing condition adjustment process is executed before the heating process for the object to be processed in the middle of the heating process in which the radioactivity amount is measured by the capacity measuring process, and the heating processing unit performs the radioactivity amount in the radioactivity measuring process. Is configured to execute the remaining heat treatment under the condition after the adjustment by the treatment condition adjustment process on the object to be processed in the middle of the heat treatment,
The heat treatment unit is composed of a conveyance type heating furnace that heats the object to be treated while conveying the object inside,
The processing target object in the middle of the heat treatment is that it is a processing target object located in the middle of the transport direction inside the transport-type heating furnace .

  According to the above configuration, since each processing unit that executes each process described in the first feature configuration described above is provided, it is possible to effectively suppress the occurrence of processing defects as in the first feature configuration. Thus, it is possible to stably remove the radioactive substance stably.

Before SL radioactivity measurement processing section may include a plurality of radioactivity measuring apparatus installed in a plurality of locations in the transport direction of the furnace.

According to the above arrangement, since the measured amount of radioactivity radioactivity measuring process previously installed radioactivity measuring apparatus in the processing object at a plurality of positions in the conveying direction of the heating furnace of the transport formula, at a plurality of setting processing progress Radioactivity can be measured easily and reliably.

Schematic configuration diagram of radioactive material removal system Graph showing the state of the processing object during heat treatment Cross-sectional schematic diagram of the heat treatment unit showing the installation form of the radioactivity measurement processing unit

FIG. 1 shows a radioactive substance removing system that executes a radioactive substance removing method for removing radioactive substances from a processing object containing radioactive substances.
In this embodiment, this radioactive substance removal system uses incineration ash generated along with incineration of waste containing radioactive substances as a processing target, and volatilizes and removes radioactive cesium (an example of a radioactive substance) from the incineration ash. It is configured.
In addition, as a process target object, it can be set as not only incineration ash but the various things containing radioactive materials, such as a waste containing the radioactive material before incineration, and soil.

  Here, “incinerated ash” means municipal waste, agricultural and forestry by-products (for example, rice straw or wheat straw), sawmill waste, dewatered sewage sludge cake, pruned branches, dead leaves, grass, paper, plastics, decontamination It means ash generated by incineration of various types of waste such as combustible waste such as tyvek or clothing used for work, disaster waste such as disaster debris, etc.

  In this radioactive substance removal system, as shown in FIG. 1, a heat treatment unit 10 for performing a heat treatment for heating the incineration ash and a radioactivity measurement process for measuring the radioactivity amount of the incineration ash during the heat treatment are performed. A radioactivity measurement processing unit 20 and a processing condition adjustment processing unit 30 for executing a processing condition adjustment process for adjusting the conditions of the heating process based on the measurement result in the radioactivity measurement process. The heat treatment for the incinerated ash is performed under an appropriate condition while optimizing the heat treatment condition by executing the treatment condition adjustment process.

  In addition, in this radioactive substance removal system, the addition process which adds the volatilization promoter which is an example of an additive to incineration ash as pre-processing of the heat processing by the heat processing part 10 is performed. Known types of volatilization accelerators to be added in the addition treatment, heating temperature in the heat treatment, etc. can be used. For example, inorganic calcium compounds or organic calcium compounds and chloride compounds can be added to the incineration ash as volatilization accelerators. For example, the heat treatment is performed at a relatively low temperature of 900 ° C. or more and 1200 ° C. or less, preferably 950 ° C. or more and 1100 ° C. or less, and a relatively short time of 30 minutes or more and 120 minutes or less, preferably 30 minutes or more and 60 minutes or less. The radioactive cesium in the incineration ash can be volatilized well.

  The said heat processing part 10 is comprised from the rotary kiln 11 which is an example of the conveyance heating furnace heated while conveying incineration ash. The heat treatment unit 10 is not limited to a conveyance type heating furnace, and various types such as a batch type heating furnace can be adopted. The rotary kiln 11 includes a substantially cylindrical kiln main body 12, a rotation drive unit 13, an incineration ash supply unit 14, an incineration ash discharge unit 15, a burner 16, an exhaust chamber 17, and the like.

  In the heat treatment, the rotary kiln 11 conveys the incineration ash supplied from the incineration ash supply unit 14 to the upstream side in the kiln main body 12 to the downstream side as the kiln main body 12 rotates. The incinerated ash from the incinerated ash is volatilized and removed, and the incinerated ash from which the radioactive cesium has been volatilized and removed is discharged from the incinerated ash discharge unit 15 on the downstream side of the kiln body 12 as a treated incinerated ash. The exhaust gas containing the volatilized radioactive cesium is discharged from the exhaust chamber 17.

  The kiln main body 12 has a downstream downward inclined posture in which the downstream end is positioned slightly below the upstream end, and conveys the incineration ash toward the downstream side while rotating the shaft with the driving force of the rotation driving unit 13. Is configured to do. The rotation drive unit 13 includes, for example, a rotation operation unit 13a such as a gear or a roller that rotates the kiln main body 12 by a driving force of a rotation drive device (not shown) such as a motor, and power of the rotation drive device. And a rotation control unit 13b for controlling the rotation speed and the number of rotations of the kiln main body 12.

  The burner 16 is installed on the downstream end side of the kiln main body 12 and generates a high-temperature combustion gas flow in the kiln main body 12 from the downstream end to the upstream. The exhaust chamber 17 is installed on the upstream end side of the kiln main body 12, and exhausts exhaust gas through the exhaust duct 18b with the power of the exhaust fan 18a. In the present embodiment, the flow of the combustion gas is countercurrent to the flow of the object to be processed, but may be a cocurrent flow.

  The incineration ash supply unit 14 includes, for example, a fixed amount supply means such as a screw feeder, and continuously supplies a fixed amount of incineration ash from the upstream end side of the kiln main body 12 to the inside of the kiln main body 12. The incineration ash discharge part 15 is composed of, for example, a hopper having a discharge port formed on the lower surface, and the processed incineration ash conveyed from the upstream side of the kiln main body 12 is moved downward from the downstream end side of the kiln main body 12. Discharge.

  Reference numeral 16a denotes a combustion control unit that controls the amount of fuel and air supplied to the burner 16, and 14a denotes a supply control unit that controls the amount of incineration ash supplied by the incineration ash supply unit 14.

  The exhaust gas discharged from the rotary kiln 11 after the heat treatment includes fine powder scattered from the main ash, and radioactive cesium volatilized in the fine powder is attached. Therefore, the fine powder having high radioactive concentration due to the attachment of radioactive cesium is collected by a bag filter or the like in the next process and stored in an intermediate storage facility or the like.

  FIG. 2 is a graph schematically showing a general relationship between the heat treatment time, the temperature of the incinerated ash, and the amount of radioactivity of the incinerated ash. As shown in FIG. 2, in this heat treatment, with the progress of the treatment, the removal of the radioactive material starts to evaporate from the vicinity where the temperature of the incinerated ash exceeds the predetermined temperature T, and then the removal of the radioactive material is continued. Will proceed.

The radioactivity measurement processing unit 20 is configured to measure a radioactivity amount at a certain point in the middle of the heat treatment as a measurement target for a part of the incinerated ash in the middle of the heat treatment as the radioactivity measurement processing. Yes. Then, as shown in FIG. 1 and FIG. 2, the radioactivity amount measurement processing unit 20 uses the radioactivity amount measurement processing for measuring the radioactivity amount of the incinerated ash as a time point during the heat treatment by the heat treatment unit 10. Are executed at a plurality of points in time t1 and t2.
Specifically, the radioactivity measurement processing unit 20 is configured such that the heat processing unit 10 is configured by a transport-type rotary kiln 11, while the heat treatment unit 10 is configured as a plurality of time points t <b> 1 and t <b> 2 having different degrees of progress of the heat processing. The axial amount measurement process is performed at a plurality of locations (a plurality of locations).
Note that this radioactivity measurement process is not limited to a plurality of time points of the heat treatment, and may be executed at one time point.

  The specific time point at which the radioactivity measurement processing unit 20 executes the radioactivity measurement processing can be set at various times. For example, the time point slightly delayed from the scheduled start time of the cesium volatilization removal (see FIG. 2 can be set to t1). If the measurement time point is set in this manner, the presence or absence of radioactive cesium volatilization removal at the measurement time point can be grasped as the state of volatilization removal of radioactive cesium.

  In addition, for example, the time point on the front stage (t1 in FIG. 2) and the time point on the rear stage (t2 in FIG. 2) in the progressing stage of volatilization and removal of radioactive cesium are set as the time points when the radioactivity measurement process is executed. You can also. If the measurement time point is set in this way, the progress (difference or tendency) of the volatilization removal of radioactive cesium can be grasped from the measurement results at a plurality of time points as the state of volatilization removal of radioactive cesium.

  Furthermore, for example, when the radioactivity measurement process is performed, as far as possible in the range where radiocesium can be appropriately removed from the incinerated ash by the heat treatment after adjusting the conditions when the heat treatment conditions are adjusted after the measurement. It is also possible to set at the point of time. By setting the measurement time point in this way, it is possible to predict very accurately whether or not a processing failure occurs within a range in which radioactive cesium can be appropriately removed from the incinerated ash.

  As shown in FIG. 1, the radioactivity measurement processing unit 20 is provided with a plurality of radioactivity measurement devices 21 having wired and wireless transmission / reception units (not shown) at a plurality of locations in the longitudinal direction of the kiln body 12. Configured. Each radioactivity measuring device 21 performs the radioactivity at the installation location (for example, radioactivity concentration Bq / kg) based on a preset measurement schedule, a control command from the control unit 31 described later, or the like as the radioactivity measurement processing. Or the space radiation dose rate μSv / h or the count rate cpm), and the measurement result is transmitted to the control unit 31.

  In the present embodiment, the radioactivity measuring device 21 uses a NaI scintillation detection device that can easily and quickly measure the space radiation dose rate, which is an example of the radioactivity. In addition, as the radioactive quantity measuring apparatus 21, the apparatus which can measure the radioactive concentration which is an example of radioactive quantity, such as a germanium semiconductor detection apparatus, the apparatus which can measure the count rate which is an example of radioactive quantity, such as GM type survey meter, etc. Various devices capable of measuring the amount of radioactivity can be applied. Space radiation dose rate and counting rate can be converted to radioactivity concentration, the measured space radiation dose rate, counting rate can be converted manually or automatically into concentration, and the heat treatment conditions can be adjusted with that value, You may adjust the conditions of heat processing with the measured air dose rate or the count rate.

  As a specific installation form of the radioactive quantity measuring device 21, various installation forms can be adopted. For example, as shown in FIG. 3A, the peripheral wall portion 12a of the fireproof structure of the kiln main body 12 rotating on the axis. As shown in FIG. 3B, the first installation mode in which the radioactive quantity measuring device 21 is attached to the floor, and the radioactive quantity measuring device 21 is attached to the installation portion 22 on the floor surface side that is not affected by the axial rotation of the kiln main body 12. Two installation forms can be adopted.

  Here, in any of the first installation mode and the second installation mode, the radioactivity measuring device 21 has a radioactivity measurement area by surrounding the detection unit on the front end side of the device with a shielding unit made of lead or the like. Reduce the amount of radioactivity so that it has directivity.

  In the first installation mode shown in FIG. 3 (a), the radioactivity measuring device 21 attached to the peripheral wall portion 12a of the kiln main body 12 rotates in the circumferential direction as the kiln main body 12 rotates. Is located in a specific part on the lower side determined to some extent by gravity in the kiln main body 12 rotating on the axis. Therefore, depending on the measurement timing caused by the axial rotation speed of the kiln main body 12, the measurement schedule of the radioactivity measuring device 21, the response speed, etc., the incineration ash is positioned from the measurement area of the radioactivity measuring device 21 with directivity. There may be a problem that the amount of radioactivity is not properly measured.

  Therefore, when such a situation is expected, the plurality of radioactive quantity measuring devices 21 are arranged at a plurality of locations in the circumferential direction of the peripheral wall portion 12a of the kiln body 12, particularly at a plurality of locations having an angular difference other than 180 degrees in the circumferential direction. It is preferable to attach. In this way, at each measurement time point, the amount of radioactivity can be measured in any one of a plurality of measurement areas by the plurality of radioactivity amount measuring devices 21, so that the above-described inconvenience is effectively suppressed. Can do.

  On the other hand, in the second installation mode shown in FIG. 3 (b), the incineration ash is assumed to be located at a specific portion on the lower side determined to some extent by gravity in the kiln main body 12 that rotates the shaft, and has directivity. It is preferable to install the radioactivity measuring device 21 so that the specific part is contained in the measurement area of the radioactivity measuring device 21. If it does in this way, the amount of radioactivity of incineration ash can be measured appropriately with a very high probability.

  The processing condition adjustment processing unit 30 adjusts the conditions of the heat treatment such as the temperature and time of the heat treatment, the amount of incinerated ash used for the heat treatment, based on the measurement result of the radioactivity measurement process as the treatment condition adjustment processing. Is configured to do. As shown in FIG. 1, the processing condition adjustment processing unit 30 includes a control unit 31 that controls the operation of the radioactive substance removal system.

  The control unit 31 includes a storage unit, a data processing unit, a transmission / reception unit (input / output unit), etc., receives various data by the transmission / reception unit, processes the data by the data processing unit, and controls the combustion control unit 16a and supply control. The operation of the radioactive substance removal system is controlled by transmitting an operation command from the transmission / reception unit to the unit 14a, the rotation control unit 13b, the exhaust fan 18a, and the like.

  When the control unit 31 receives the radioactivity measurement data from the radioactivity measurement process from the radioactivity measurement device 21, as the processing condition adjustment process, first, the measurement data is processed by the data processing unit and stored in the storage unit. A determination process for determining suitability of the heat treatment condition at the time of measurement is performed by comparing with data. In the case where the measurement data is the space radiation dose rate, in this determination process, the radioactivity concentration may be converted from the correlation between the radioactivity concentration stored in the storage unit and the space radiation dose rate.

  And if the control part 31 determines with the conditions of the heat processing at the time of a measurement being unsuitable in this determination process, the change process which transmits the operation | movement command which changes the conditions of heat processing to the side which volatilization removal of a radioactivity will progress further. I do. By performing the determination process and the change process in this manner, the control unit 31 optimizes the conditions of the heat treatment for the incinerated ash and suppresses the generation of defective processing after the heat treatment.

  The change process for the heat treatment condition performed by the control unit 31 may be various processes that can optimize the volatilization and removal of radioactive cesium. Specific examples include the following (A) to (C). Can do.

  (A) The control unit 31 issues an operation command for reducing the rotation speed of the kiln body 12 to the rotation control unit 13b as a change process for the heat treatment condition. Due to the decrease in the rotational speed of the kiln main body 12 due to this operation command, the conveying speed of the incineration ash decreases, and as a result, the heating time of the incineration ash is extended. By extending the heating time of the incineration ash, volatilization and removal of radioactive cesium further proceeds.

  (B) The control unit 31 performs an operation command to reduce the amount of incinerated ash supplied to the kiln body 12 to the supply control unit 14a as a change process for changing the heat treatment condition. By reducing the amount of incinerated ash supplied to the kiln main body 12 by this operation command, the amount of incinerated ash heated in the kiln main body 12 is reduced, the heat capacity in the kiln main body 12 is reduced, and as a result, the temperature of the incinerated ash increases. Is done. Due to the high temperature of the incineration ash, the volatilization and removal of radioactive cesium further proceeds.

  (C) The control unit 31 issues an operation command to increase the output of the burner 16 to the combustion control unit 16a as a change process for changing the heat treatment condition. As the output of the burner 16 is increased by this operation command, the incineration ash is heated to a high temperature. Due to the high temperature of the incineration ash, the volatilization and removal of radioactive cesium further proceeds.

  Each of the processes (a) to (c) may be performed by selecting only one of the processes, or may be performed by appropriately setting three processes. In any of these cases, the selection order and the priority order are preferably in the order of (A), (B), and (C).

  In addition, these treatments (a) to (c) may be performed in a composite manner, and in addition to other measurement data such as the temperature of the incinerated ash other than the measurement data of the radioactivity, Appropriate ones from the processes (a) to (c) may be determined in a multifaceted manner.

  The execution timing of the processing condition adjustment processing by the control unit 31 can be set as appropriate according to the operating environment of the radioactive substance removal system, but in this embodiment, for example, real-time substantially simultaneously with the radioactivity measurement processing By executing the process condition adjustment process in the form, the process condition adjustment process is executed before the heating process for the incinerated ash whose radioactivity is measured in the radioactivity measurement process is completed.

  By performing the process condition adjustment process before the heat treatment for the incinerated ash whose radioactivity has been measured by the radioactivity measurement process, the remaining heating for the processing object whose radioactivity has been measured by the radioactivity measurement process is completed. The treatment can be made appropriate, and the incineration ash whose amount of radioactivity has been measured by the remaining heat treatment can be prevented from becoming defective.

  It should be noted that the specific adjustment contents of the heat treatment conditions in this treatment condition adjustment processing may be any as long as the heat treatment conditions are changed to the side where the volatilization removal of radioactivity becomes appropriate. However, for example, the remaining amount of the heat treatment for the incinerated ash is calculated from the progress of the heat treatment at the time of execution of the radioactive amount measurement processing, and the amount of radioactivity of the incinerated ash becomes a predetermined value or less with the remaining amount of the heat treatment. The heat treatment conditions can be adjusted. Separately from this, when the incineration ash newly supplied to the heat treatment unit 10 after the execution of the radioactivity measurement process is performed from the beginning to the end, the radioactivity amount of the incineration ash is below a predetermined value. It is also possible to adjust the heat treatment conditions so that

[Another embodiment]
(1) In the above-described embodiment, the defective radioactive material after the heat treatment is treated as a defective treatment, and the heat treatment conditions are set so that the volatilization and removal of the radioactivity further proceeds by executing the treatment condition adjustment processing. Although the example of adjustment is shown as an example, for the purpose of reducing energy consumption, the removal of radioactive material after heat treatment is regarded as defective processing, and the progress of removal of radioactivity by progress of processing condition adjustment processing Heat treatment conditions may be adjusted on the slowing side to avoid an increase in energy consumption due to excessive heat treatment. In addition, if a defective treatment with insufficient removal of radioactive material occurs, it may be reheated without discharging from the radioactive material removal system as it is, and a defective treatment with insufficient removal of radioactive material may be removed. You may convey to the upstream of the heat processing part 10, and may perform heat processing again.

  (2) In the above-described embodiment, in order to carry out the radioactivity measurement process at a plurality of time points with different degrees of progress of the heat treatment, the heat treatment unit 10 is a transfer-type heating furnace, and the radioactivity measurement is performed at a plurality of locations in the transfer direction. Although the case where the process is executed is shown as an example, for example, when the heat processing unit 10 is a batch-type heating furnace, the radioactivity measurement process may be executed a plurality of times at the same location with a time interval.

  (3) In the above-described embodiment, the case where the radioactivity amount measurement processing at a plurality of points in time is executed by the plurality of radioactivity amount measurement devices 21 installed in advance in a plurality of locations in the conveyance direction of the heating furnace is described as an example. Two radioactivity measuring devices 21 are installed so as to be movable in the conveying direction of the heating furnace, and the radioactivity measuring processing at a plurality of time points is executed while moving this one radioactivity measuring device 21 to a plurality of locations in the conveying direction. Also good.

  (4) The radioactivity measurement process is not limited to being automatically executed by the radioactivity measurement processing unit 20 shown in the above-described embodiment, but may be performed by a worker using a portable radioactivity measurement apparatus. May be. Similarly, the processing condition adjustment processing is not limited to being automatically executed by the processing condition adjustment processing unit 30 shown in the above-described embodiment, but may be executed by a manual switch operation by an operator. Good.

  (5) In the above-described embodiment, the case where the heating time of the incineration ash and the temperature of the incineration ash are adjusted as an example of the adjustment of the heat treatment conditions in the processing condition adjustment processing. You may make it adjust the addition amount of the additive to add.

10 Heat treatment section 11 Conveying heating furnace (rotary kiln)
20 Radioactivity measurement processing unit 21 Radioactivity measurement device 30 Processing condition adjustment processing unit

Claims (3)

A radioactive substance removing method for performing a heat treatment for heating a processing object containing a radioactive substance,
Based on the measurement result of the radioactivity amount of the treatment object in the middle of the heat treatment, and the measurement result of the radioactivity amount of the treatment object in the middle of the heat treatment in the radioactivity measurement processing A processing condition adjustment process for adjusting the conditions, and the processing condition adjustment process is performed before the heating process for the object to be processed in the middle of the heating process in which the radioactivity is measured in the radioactivity measurement process is completed. Then, the remaining heat treatment is performed under the conditions after the adjustment by the treatment condition adjustment processing on the processing object in the middle of the heat treatment in which the radioactivity amount is measured by the radiation amount measurement processing,
The heat treatment is a treatment for heating the object to be treated while being conveyed inside a conveying heating furnace,
The radioactive substance removal method which is the process target object in the middle of the conveyance direction in the inside of the said conveyance type heating furnace in the middle of the said heat processing . The radioactive substance removal according to claim 1 , wherein, as the processing condition adjustment processing, the transport speed of the processing object inside the transport-type heating furnace or the temperature of the processing object inside the transport-type heating furnace is adjusted. Method. A radioactive substance removal system for performing a heat treatment for heating a processing object containing a radioactive substance,
A heat treatment unit that performs the heat treatment, a radioactivity measurement processing unit that performs a radioactivity measurement process that measures a radioactivity amount of a processing object in the middle of the heat treatment, and the heat treatment in the radioactivity measurement process A processing condition adjustment processing unit that executes a processing condition adjustment process that adjusts the condition of the heat treatment based on the measurement result of the amount of radioactivity of the processing object in the middle of the processing condition adjustment unit, the processing condition adjustment processing unit The processing condition adjustment process is executed before the heating process for the object to be processed in the middle of the heating process in which the radioactivity amount is measured by the capacity measuring process, and the heating processing unit performs the radioactivity amount in the radioactivity measuring process. Is configured to execute the remaining heat treatment under the condition after the adjustment by the treatment condition adjustment process on the object to be processed in the middle of the heat treatment,
The heat treatment unit is composed of a conveyance type heating furnace that heats the object to be treated while conveying the object inside,
The radioactive substance removal system which is a process target object in the location in the middle of the conveyance direction in the inside of the said conveyance type heating furnace in the middle of the said heat processing .

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